322 PLANTS PRODUCING GUMS AND RESINS 



It burns in the flame of a candle and melts at about 340° C. without 

 decomposing. At 360° C. it yields products of decomposition (copal 

 oil). It is only partially soluble in alcohol, and leaves a residue of 

 60 to 67 per cent. ; it is more soluble in ether, essential and non- 

 volatile oils. 



Copal is chiefly used in the manufacture of varnishes. It is melted 

 and dissolved in linseed oil heated to 150° C. with essence of turpentine 

 added. 



The commercial West African coj^als are : — 



Accra co-pal, usually green coloured, in small demand. 



Sierra Leone co-pal, colour varying from yellow to tawny brown ; 

 melts at 180° to 185° C. ; used for fine varnishes. 



Congo copal, quality very variable ; the best is very hard, trans- 

 parent, almost colourless; melts at 140° to 150° C. 



Angola copalj red variety in great demand, white variety less valu- 

 able. 



Yellow Bcngiiela copal, colour varying from pale to greenish 

 yellow. In great demand in England and Holland. 



Copaifera Mopane. — It is from this species of Copaifera that Angola 

 copal is derived. According to Welwitsch, it exudes a blood-coloured 

 resin, comparable with dragon's blood. 



We learn from de Cordemoy that C. Mopane inhabits the dry and 

 desert lands of Southern Africa. In the west it thrives in the dry 

 and sandy territory to the north of Cunene and in the neighbourhood 

 of Mossamedes. Towards the east, according to Kirk, it forms on the 

 banks of the Zambesi vast forests extending over dry and barren 

 plains. 



Detarium senegalense — One of the gummiferous plants of Senegal. 

 This gum is sufliciently abundant to support an industry, but up to the 

 present no commercial use has been made of either this product or that 

 of Cords'la ajricana. 



Hymenaea verrucosa — Produces the Madagascar copal. It is a 

 very large tree with a straight cylindrical trunk which may, at i metre 

 above the ground, measure as much as 2' 50 metres in circumference. 

 It is from 35 to 40 metres high. The natives usually prefer to exploit 

 the hard semi-fossil copal, stores of which have accumulated at the 

 foot of the tree; they do not beat the bark, but are content merely to 

 cut it in order to obtain as much resin as possible. 



The copal tree is very widely distributed throughout M^adagascar, 

 but it is especially abundant in the north and along the eastern slope. 



The natives are acquainted with the use made of copal, and employ 

 it to varnish furniture. 



In the market it is more than likely that green copal and fossil 

 copal are mixed. In the province of Andcvorante there is a large 

 amount of copal which fetches 50 francs per 100 kilos, and in the 

 market of Mananjary the same amount fetciies 30 francs. At Tama- 

 tave it is sold at 75 francs per 50 kilos; 4,680 kilos were exported 

 in 1807. 



